阅读说明：本技术 通过微反应器合成氧杂环丁烷化合物的方法 (Method for synthesizing oxetane compounds through microreactor ) 是由 钱晓春 王兵 陈君 魏亮 于 2021-02-10 设计创作，主要内容包括：本发明提供了一种通过微反应器合成氧杂环丁烷化合物的方法。该合成方法包括：在碱性催化剂存在下,将三羟甲基丙烷和碳酸酯通入微反应器中,并在惰性溶剂或无溶剂条件下通过微反应连续流工艺合成所述氧杂环丁烷化合物。相对于常规反应器,微反应器具有传热传质系数高,混合性能好,温度容易控制和过程安全可控等优点。利用微反应器的优势进行上述三种氧杂环丁烷产品的生产,可大幅提高反应体系传质传热性,减少反应时间提高生产效率,尤其避免了裂解工序中长时间的高温过程,减少高沸点副产物的产生,提高了收率,并实现过程的连续化、自动化,提高过程安全性。上述合成过程所需的反应装置体积小,生产场地占用面积小,安全性高。(The invention provides a method for synthesizing an oxetane compound through a microreactor. The synthesis method comprises the following steps: trimethylolpropane and carbonate are introduced into a microreactor in the presence of a basic catalyst, and the oxetane compound is synthesized by a microreaction continuous flow process under inert solvent or solvent-free conditions. Compared with the conventional reactor, the microreactor has the advantages of high heat and mass transfer coefficients, good mixing performance, easy temperature control, safe and controllable process and the like. The advantages of the microreactor are utilized to produce the three oxetane products, so that the mass transfer and heat transfer properties of a reaction system can be greatly improved, the reaction time is shortened, the production efficiency is improved, particularly, the long-time high-temperature process in a cracking process is avoided, the generation of high-boiling-point byproducts is reduced, the yield is improved, the continuity and automation of the process are realized, and the process safety is improved. The reaction device required by the synthesis process is small in size, small in occupied area of a production field and high in safety.)

1. A method for synthesizing an oxetane compound through a microreactor, characterized in that trimethylolpropane and carbonate are fed into the microreactor in the presence of a basic catalyst, and the oxetane compound is synthesized by a microreaction continuous flow process under solvent or solvent-free conditions.

2. The method for synthesizing an oxetane compound through a microreactor as claimed in claim 1, wherein the basic catalyst comprises a first basic catalyst and a second basic catalyst, and the method for synthesizing an oxetane compound through a microreactor comprises:

continuously conveying the first basic catalyst, the trimethylolpropane and the carbonic ester to a first microreactor for transesterification reaction to obtain a reaction product system containing an esterification intermediate;

extracting the esterified intermediate from the reaction product system containing the esterified intermediate;

conveying the esterification intermediate and the second basic catalyst to a second microreactor for a cracking reaction to obtain a cracking reaction product system;

and carrying out gas-liquid separation treatment on the cracking reaction product system to obtain the oxetane compound.

3. The method for synthesizing an oxetane compound through a microreactor as claimed in claim 1, wherein the solvent is one or more of the group consisting of halogenated hydrocarbon, benzene, toluene, xylene, nitrobenzene, acetonitrile.

4. The method for synthesizing an oxetane compound through a microreactor as claimed in claim 2, wherein the temperature of the first microreactor is 50-300 ℃ and the residence time is 1-60 min; the reaction temperature of the second micro-reactor is 150-400 ℃, and the residence time is 1-8 min.

5. The method for synthesizing an oxetane compound in a microreactor according to claim 4, wherein the temperature of the first microreactor is 100 to 200 ℃; the reaction temperature of the second microreactor is 200-300 ℃.

6. The method for synthesizing an oxetane compound in a microreactor according to any of claims 2 and 4 to 5, wherein the molar ratio of trimethylolpropane to the carbonate is 1 (1 to 5), and the content of the basic catalyst is 100ppm to 50000 ppm.

7. The method for synthesizing an oxetane compound in a microreactor according to claim 6, wherein the molar ratio of trimethylolpropane to the carbonate is 1 (1.5 to 3) and the content of the basic catalyst is 100ppm to 10000 ppm.

8. The method for synthesizing an oxetane compound in a microreactor according to claim 6 or 7, wherein the carbonate is one or more selected from the group consisting of dimethyl carbonate, diethyl carbonate and dipropyl carbonate;

the alkaline catalyst is selected from one or more of alkali metal hydroxide, sodium alkoxide, potassium alkoxide and alkali metal carbonate.

9. The method for synthesizing an oxetane compound through a microreactor of claim 8, wherein the first basic catalyst and the second basic catalyst are each independently selected from one or more of hydroxides of alkali metals, sodium alkoxides, potassium alkoxides, carbonates of alkali metals, preferably, the first basic catalyst and the second basic catalyst are each independently selected from one or more of the group consisting of sodium methoxide, sodium ethoxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate;

preferably, the dosage of the first basic catalyst is 200-500 ppm, and the dosage of the second basic catalyst is 300-3000 ppm.

10. The method for synthesizing an oxetane compound through a microreactor as claimed in claim 2, wherein the synthesizing method further comprises, during the conducting of the cracking reaction: and adding water into the esterification intermediate, wherein the water content of the system in the cracking reaction process is 10-100000 ppm.

11. The method for synthesizing an oxetane compound through microreactor as claimed in any of claims 2 to 5, wherein the inner diameter of the reaction channel of the first microreactor is selected from 200 to 10000 μm, and the inner diameter of the reaction channel of the second microreactor is selected from 200 to 10000 μm;

preferably, the inner diameter of the reaction channel of the first microreactor is selected from 200-2000 μm, and the inner diameter of the reaction channel of the second microreactor is selected from 500-10000 μm.

12. The method for synthesizing an oxetane compound through a microreactor as claimed in claim 2, wherein the extraction process employs an apparatus selected from a thin film evaporator or a rectifying tower.

Technical Field

The invention relates to the field of organic synthesis, in particular to a method for synthesizing an oxetane compound through a microreactor.

Background

3-ethyl-3-hydroxymethyl oxetane and bis [ 1-ethyl (3-oxetanyl) methyl ] ether are the most used monomers of the current photo-curing cationic system, are widely applied to the fields of photo-curing coatings, printing inks, adhesives and the like, and have the following structural formula:

the cyclic carbonate cracking method is widely used in industry to prepare oxetane products. The reaction process for producing 3-ethyl-3-hydroxymethyl oxetane by cyclic carbonate cracking method is as follows:

wherein R is an alkyl group, typically methyl or ethyl.

The process flow is as follows: carrying out ester exchange reaction on trimethylolpropane and carbonic ester in a rectifying still at the temperature of 80-120 ℃, continuously fractionating by-product alcohol in the reaction process, distilling to remove excessive carbonic ester after the reaction is finished, wherein the ester exchange process needs 10-12 h, then entering a cracking process, cracking at the temperature of 160-200 ℃ for 12-15 h to remove carbon dioxide, and finally rectifying under negative pressure to obtain a finished product. The whole process can be completed within 30-40 h, and the production efficiency is low. The cracking reaction is carried out at high temperature for a long time, which can result in the production of high-boiling-point by-products, so that the yield of the finished product is low (65-75%), and a large amount of distillation residues are produced after the rectification is finished and can only be treated as solid waste.

In view of the above problems, it is desirable to provide a method for synthesizing an oxetane compound in a high yield and in a short reaction time.

Disclosure of Invention

The invention mainly aims to provide a method for synthesizing an oxetane compound through a microreactor, which aims to solve the problems of low yield and long reaction time of the existing synthesis method of the oxetane compound, and further provides a method for adjusting the distribution of products by controlling related parameters in the reaction process on the basis of the problem, so as to realize the co-production of three oxetane compounds.

In order to achieve the above object, according to the present invention, there is provided a method for synthesizing an oxetane compound by a microreactor, comprising introducing trimethylolpropane and carbonate into a microreactor in the presence of a basic catalyst, and synthesizing an oxetane compound by a microreaction continuous flow process under a solvent or solvent-free condition.

Further, the basic catalyst comprises a first basic catalyst and a second basic catalyst, and the method for synthesizing the oxetane compound through the microreactor comprises the following steps: continuously conveying the first basic catalyst, trimethylolpropane and carbonic ester to a first microreactor for transesterification reaction to obtain a reaction product system containing an esterification intermediate; extracting an esterified intermediate from a reaction product system containing the esterified intermediate; conveying the esterification intermediate and a second basic catalyst to a second microreactor for a cracking reaction to obtain a cracking reaction product system; and carrying out gas-liquid separation treatment on the cracking reaction product system to obtain the oxetane compound.

Further, the solvent is one or more of the group consisting of halogenated hydrocarbon, benzene, toluene, xylene, nitrobenzene and acetonitrile.

Further, the temperature of the first micro-reactor is 50-300 ℃, and the residence time is 1-60 min; the reaction temperature of the second micro-reactor is 150-400 ℃, and the residence time is 1-8 min.

Further, the temperature of the first micro-reactor is 100-200 ℃; the reaction temperature of the second micro-reactor is 200-300 ℃.

Further, the molar ratio of trimethylolpropane to carbonate is 1 (1-5), and the content of the basic catalyst is 100 ppm-50000 ppm.

Further, the molar ratio of trimethylolpropane to carbonate is 1 (1.5-3), and the content of the alkaline catalyst is 100 ppm-10000 ppm.

Further, the carbonate is selected from one or more of the group consisting of dimethyl carbonate, diethyl carbonate and dipropyl carbonate; the alkaline catalyst is selected from one or more of alkali metal hydroxide, sodium alkoxide, potassium alkoxide or alkali metal carbonate.

Further, the first basic catalyst and the second basic catalyst are respectively and independently selected from one or more of alkali metal hydroxide, sodium alkoxide, potassium alkoxide or alkali metal carbonate, preferably, the first basic catalyst and the second basic catalyst are respectively and independently selected from one or more of sodium methoxide, sodium ethoxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate and potassium carbonate; preferably, the first basic catalyst is used in an amount of 200 to 500ppm, and the second basic catalyst is used in an amount of 300 to 3000 ppm.

Further, in the process of carrying out the cracking reaction, the synthesis method further comprises the following steps: and adding water into the esterification intermediate, wherein the water content of the system in the cracking reaction process is 10-100000 ppm.

Further, the inner diameter of the reaction channel of the first micro-reactor is selected from 200-10000 μm, and the inner diameter of the reaction channel of the second micro-reactor is respectively and independently selected from 200-10000 μm; preferably, the inner diameter of the reaction channel of the first microreactor is selected from 200-2000 μm, and the inner diameter of the reaction channel of the second microreactor is selected from 500-10000 μm.

Further, the device adopted in the extraction process is selected from a thin film evaporator or a rectifying tower.

Compared with the conventional reactor, the micro-reactor has the advantages of high heat and mass transfer coefficient, good mixing performance, easy temperature control, safe and controllable process and the like. The advantages of the microreactor are utilized to produce the three oxetane products, so that the mass transfer and heat transfer properties of a reaction system can be greatly improved, the reaction time is shortened, the production efficiency is improved, particularly, the long-time high-temperature process in a cracking process is avoided, the generation of high-boiling-point byproducts is reduced, the yield is improved, the continuity and automation of the process are realized, and the process safety is improved. In addition, the reaction device required by the synthesis process is small in size, small in occupied area of a production field, less in required human resources and high in safety.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic configuration diagram of an apparatus for synthesizing an oxetane compound provided according to an exemplary embodiment of the present invention.

Wherein the figures include the following reference numerals:

10. a raw material storage tank; 11. a first feed pump; 20. a first microreactor; 30. a thin film evaporator; 40. an esterification intermediate storage tank; 41. a second feed pump; 50. a light-boiling-point substance collecting tank; 60. a second microreactor; 70. a micro heat exchanger; 80. a gas-liquid separation tank; 90. a rectification device.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As described in the background art, the existing synthesis methods of oxetane compounds have problems of low yield and long reaction time. In order to solve the above technical problems, the present application provides a method for synthesizing an oxetane compound by a microreactor, the method comprising: trimethylolpropane and carbonate are introduced into a microreactor in the presence of a basic catalyst, and an oxetane compound is synthesized by a microreaction continuous flow process under inert solvent or solvent-free conditions.

Compared with the conventional reactor, the microreactor has the advantages of high heat and mass transfer coefficients, good mixing performance, easy temperature control, safe and controllable process and the like. The advantages of the microreactor are utilized to produce the three oxetane products, so that the mass transfer and heat transfer properties of a reaction system can be greatly improved, the reaction time is shortened, the production efficiency is improved, particularly, the long-time high-temperature process in a cracking process is avoided, the generation of high-boiling-point byproducts is reduced, the yield is improved, the continuity and automation of the process are realized, and the process safety is improved. In addition, the reaction device required by the synthesis process is small in size, small in occupied area of a production field, less in required human resources and high in safety.

In a preferred embodiment, the basic catalyst comprises a first basic catalyst and a second basic catalyst, and the method for synthesizing an oxetane compound through a microreactor comprises: continuously conveying the first basic catalyst, trimethylolpropane and carbonic ester to a first microreactor for transesterification reaction to obtain a reaction product system containing an esterification intermediate; extracting an esterified intermediate from a reaction product system containing the esterified intermediate; conveying the esterification intermediate and a second basic catalyst to a second microreactor for a cracking reaction to obtain a cracking reaction product system; and carrying out gas-liquid separation treatment on the cracking reaction product system to obtain the oxetane compound.

After the gas-liquid separation, the obtained product is a mixture, and the product can be further separated as required by a person skilled in the art. Methods of separation include, but are not limited to, distillation.

The solvent used in the above synthesis method may be any one commonly used in the art. In a preferred embodiment, the solvent includes, but is not limited to, one or more of the group consisting of halogenated hydrocarbons, benzene, toluene, xylene, nitrobenzene, acetonitrile. For cost reasons, solvent-free conditions are preferred.

In a preferred embodiment, the temperature of the first microreactor is 50-300 ℃, and the residence time is 1-60 min; the reaction temperature of the second micro-reactor is 150-400 ℃, and the residence time is 1-8 min. Compared with uncontrollable product composition in the conventional process, the process conditions of the ester exchange reaction and the cracking reaction process are limited in the range, so that the total yield of the oxetane product can be improved, different product distributions can be controlled by adopting the method, the co-production of three oxetane compounds can be realized, and the economic value of the oxetane compound is improved. For example, the temperature of the first microreactor may be 50 ℃, 80 ℃, 100 ℃, 160 ℃, 200 ℃, 300 ℃; the reaction temperature of the second micro-reactor can be 150 ℃, 200 ℃, 260 ℃, 300 ℃ and 400 ℃.

In a preferred embodiment, the temperature of the first microreactor is 100-200 ℃; the reaction temperature of the second micro-reactor is 200-300 ℃. The temperature of the first microreactor and the temperature of the second microreactor include, but are not limited to, the ranges described above, and limiting the temperatures to the ranges described above is advantageous for further improving the yield of the target product and shortening the reaction time.

In a preferred embodiment, the molar ratio of trimethylolpropane to carbonate in the transesterification reaction is 1 (1-5), and the content of the basic catalyst is 100ppm to 50000 ppm. The amount of trimethylolpropane, carbonate and basic catalyst includes, but is not limited to, the above range, and it is preferable to further increase the conversion rate of the reaction raw material by limiting the amount to the above range. More preferably, the molar ratio of trimethylolpropane to carbonate is 1 (1.5-3), and the content of the basic catalyst is 100 ppm-10000 ppm.

In the above synthesis method, the carbonate and the basic catalyst may be those commonly used in the art. In a preferred embodiment, the carbonate includes, but is not limited to, one or more of the group consisting of dimethyl carbonate, diethyl carbonate, and dipropyl carbonate.

In a preferred embodiment, the first basic catalyst and the second basic catalyst are each independently selected from one or more of alkali metal hydroxides, sodium alkoxides, potassium alkoxides, and alkali metal carbonates. More preferably, the first basic catalyst and the second basic catalyst are each independently selected from one or more selected from the group consisting of sodium methoxide, sodium ethoxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, and potassium carbonate.

In order to further improve the catalytic effect and shorten the reaction time, it is further preferable that the first basic catalyst and the second basic catalyst are respectively and independently selected from one or more of sodium methoxide, sodium ethoxide, sodium hydroxide or potassium hydroxide; the dosage of the first basic catalyst is 200-500 ppm, and the dosage of the second basic catalyst is 300-3000 ppm.

In a preferred embodiment, the above synthesis method further comprises, during the cleavage reaction: adding water into the esterification intermediate, wherein the water content of the system in the cracking reaction process is 10-100000 ppm. Limiting the water content of the system during the cleavage reaction to the above range is advantageous for increasing the cleavage rate of the esterification intermediate, and thus for increasing the yield of the oxetane compound, as compared to other ranges.

In a preferred embodiment, the first microreactor has an internal reaction channel diameter selected from 200 to 10000 μm and the second microreactor has an internal reaction channel diameter selected from 200 to 10000 μm. The limitation of the reaction channel of the first microreactor and the reaction channel of the second microreactor within the above-mentioned ranges is advantageous in increasing the yield of the target product as compared with other ranges. For example, the internal diameter of the reaction channel of the first microreactor may be selected from 200 μm, 500 μm, 1000 μm, 5000 μm, 10000 μm, and the internal diameter of the reaction channel of the second microreactor may be selected from 200 μm, 500 μm, 1000 μm, 8000 μm, 10000 μm. More preferably, the inner diameter of the reaction channel of the first microreactor is selected from 200 to 2000 μm, and the inner diameter of the reaction channel of the second microreactor is selected from 500 to 10000 μm.

In order to further improve the purity of the target product and reduce the energy consumption of the synthesis method, preferably, the synthesis method further comprises the steps of carrying out heat exchange on the cracking reaction product system in a micro heat exchanger, removing carbon dioxide through a gas-liquid separation device, and rectifying to obtain the required product.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

The microchannel apparatus system used in examples 1 to 5 was a model of Shanghai Technology, Inc., TMP/S3047-32-3/A2000, and the first microreactor had a channel inner diameter of 1000 μm and the second microreactor had a channel inner diameter of 8000 μm.

In the examples, an oxetane compound was prepared using the apparatus shown in fig. 1, and the synthesis method included:

an ester exchange section: mixing Trimethylolpropane (TMP) and dimethyl carbonate (DMC) according to a certain molar ratio, adding a metered alkaline catalyst according to the weight of the TMP, uniformly mixing, placing in a raw material storage tank 10 for preheating, adding into a first microreactor 20 through a first feeding pump 11 for carrying out ester exchange reaction, and staying for a certain time to obtain a reaction product system containing an esterified intermediate; the reaction product system containing the esterification intermediate is separated into methanol and residual DMC by a thin film evaporator 30, the recovered raw material is placed in a light boiling substance collection tank 50, and the esterification intermediate is stored in an esterification intermediate storage tank 40.

A cracking section: adding an alkaline catalyst into the esterified intermediate, selectively adding a proper amount of water, uniformly mixing, adding the mixture into a second microreactor 60 through a second feeding pump 41, staying for a certain time for a cracking reaction, cooling the mixture through a micro-heat exchanger 70, and then feeding the cooled mixture into a gas-liquid separation tank 80 to separate carbon dioxide to obtain a crude product;

product separation: and (4) conveying the crude product to a rectifying device 90 for rectifying and separating to obtain a corresponding product.

The process parameters in examples 1 to 5 are shown in Table 1.

TABLE 1

The product structure in table 1 is as follows: and (3) a product A: 3-Ethyl-3-hydroxymethyl-oxetane

And (3) a product B: bis [ 1-ethyl (3-oxetanyl) methyl]Ether compounds

Product C bis [ 1-ethyl (3-oxetanyl) methyl carbonate]Esters

Example 6

The differences from example 1 are: the reaction temperature for the transesterification reaction was 80 ℃ and the temperature for the cleavage reaction was 300 ℃.

The total yield of the product was 83.4%, and the ratios (%) of the products A, B and C were 95.7%, 1.2% and 3.1%, respectively.

Example 7

The differences from example 1 are: the reaction temperature for the transesterification reaction was 160 ℃ and the temperature for the cleavage reaction was 260 ℃.

The total yield of the product was 90.8%, and the ratios (%) of the products A, B and C were 92.0%, 4.6% and 3.4%, respectively.

Example 8

The differences from example 1 are: the molar ratio of trimethylolpropane to carbonate was 1:1 and the amount of basic catalyst for transesterification was 800 ppm.

The total yield of the product was 80.7%, and the ratios (%) of the products A, B and C were 94.5%, 3.3% and 2.2%, respectively.

Example 9

The differences from example 1 are: the molar ratio of trimethylolpropane to carbonate was 1:5, and the amount of basic catalyst for transesterification was 100 ppm.

The total yield of the product was 84.7%, and the ratios (%) of the products A, B and C were 95.1%, 2.9% and 2.0%, respectively.

Example 10

The differences from example 1 are: the reaction temperature of the ester exchange reaction is 50 ℃, the retention time of the ester exchange reaction is 60min, and the temperature of the cracking reaction is 400 ℃.

The total yield of the product was 85.7%, and the ratios (%) of the products A, B and C were 98.3%, 1.3% and 0.4%, respectively.

Example 11

The differences from example 1 are: the reaction temperature of the transesterification reaction was 300 ℃, the residence time of the transesterification reaction was 1min, and the temperature of the cleavage reaction was 200 ℃.

The total yield of the product was 86.2%, and the ratios (%) of the products A, B and C were 39.5%, 46.9% and 13.6%, respectively.

Example 12

The differences from example 1 are: the reaction temperature of the ester exchange reaction is 200 ℃, the retention time of the ester exchange reaction is 30min, and the temperature of the cracking reaction is 150 ℃.

The total yield of the product was 96.8%, and the ratios (%) of the products A, B and C were 29.3%, 50.1% and 20.6% in this order.

Example 13

The differences from example 1 are: the content of the basic catalyst for the transesterification was 50000 ppm.

The total yield of the product was 91.3%, and the ratios (%) of the products A, B and C were 95.2%, 2.0% and 2.8%, respectively.

Example 14

The differences from example 1 are: the content of the basic catalyst in the ester exchange reaction was 10000 ppm.

The total yield of the product was 93.4%, and the ratios (%) of the products A, B and C were 96.8%, 1.2% and 2.0%, respectively.

Example 15

The differences from example 1 are: the content of the basic catalyst for the transesterification was 30000 ppm.

The total yield of the product was 91.8%, and the ratios (%) of the products A, B and C were 95.3%, 1.6% and 3.1%, respectively.

Example 16

The differences from example 1 are: the content of the basic catalyst for the transesterification reaction was 8000 ppm.

The total yield of the product was 93.1%, and the ratios (%) of the products A, B and C were 96.0%, 1.8% and 2.2%, respectively.

Example 17

The differences from example 1 are: the content of the basic catalyst for the transesterification was 5000 ppm.

The total yield of the product was 92.8%, and the ratios (%) of the products A, B and C were 96.2%, 1.9% and 2.3%, respectively.

Example 18

The differences from example 1 are: the first microreactor reaction channel has an internal diameter of 100 μm and the second microreactor reaction channel has an internal diameter of 100 μm.

The total yield of the product was 81.3%, and the ratios (%) of the products A, B and C were 95.6%, 1.0% and 3.4%, respectively.

Example 19

The differences from example 1 are: the first microreactor reaction channel has an internal diameter of 10000 μm and the second microreactor reaction channel has an internal diameter of 10000 μm.

The total yield of the product was 91.8%, and the ratios (%) of the products A, B and C were 95.5%, 2.0% and 2.5%, respectively.

Example 20

The differences from example 1 are: the first microreactor reaction channel has an internal diameter of 200 μm and the second microreactor reaction channel has an internal diameter of 200 μm.

The total yield of the product was 90.7%, and the ratios (%) of the products A, B and C were 94.9%, 2.1% and 3.0%, respectively.

Example 21

The differences from example 1 are: the catalyst for the cracking reaction was sodium methoxide with a content of 1000ppm, and the water content for the cracking reaction was 100000 ppm.

The total yield of the product was 93.5%, and the ratios (%) of the products A, B and C were 97.2%, 2.0% and 0.8%, respectively.

Example 22

The differences from example 1 are: the catalyst for the ester exchange reaction is sodium methoxide, the content is 10000ppm, the catalyst for the cracking reaction is sodium methoxide, the content is 1000ppm, and the water content of the cracking reaction is 100000 ppm.

The total yield of the product was 95.8%, and the ratios (%) of the products A, B and C were 97.5%, 1.9% and 0.6%, respectively.

Example 23

The differences from example 1 are: the catalyst of the ester exchange reaction is sodium methoxide, the content is 10000ppm, the catalyst of the cracking reaction is sodium methoxide, the content is 300ppm, and the water content of the cracking reaction is 10 ppm.

The total yield of the product was 96.5%, and the ratios (%) of the products A, B and C were 3.5%, 94.6% and 1.9%, respectively.

Example 24

The differences from example 1 are: the temperature of the cleavage reaction was 100 ℃.

The total yield of the product was 66.8%, and the ratios (%) of the products A, B and C were 3.9%, 1.7% and 94.4%, respectively.

Example 25

The differences from example 1 are: the temperature of the cleavage reaction was 450 ℃.

The total yield of the product was 82.9%, and the ratios (%) of the products A, B and C were 43.4%, 56.5% and 0.1%, respectively.

Example 26

The differences from example 1 are: the temperature of the transesterification was 30 ℃.

The total yield of the product was 78.6%, and the ratios (%) of the products A, B and C were 94.1%, 2.4% and 3.5%, respectively.

Example 27

The differences from example 1 are: the temperature of the transesterification was 350 ℃.

The total yield of the product was 79.0%, and the ratios (%) of the products A, B and C were 94.5%, 2.6% and 2.9%, respectively.

In the comparative example, an oxetane compound was prepared using a conventional reaction apparatus, and the synthesis method included:

(1) an ester exchange section: adding TMP, DMC and toluene into a stainless steel stirring kettle with a rectifying tower and a condenser, stirring uniformly, adding a catalyst, heating for reaction, collecting generated methanol at the tower top, heating for distillation after no methanol is distilled off at the tower top, and removing the solvent toluene and the residual DMC by continuous heating distillation to obtain an esterification intermediate;

(2) a cracking section: adding alkaline catalyst, selectively adding proper amount of water, cracking at a certain temperature and under negative pressure, and distilling to obtain the product. The process parameters in comparative examples 1 to 5 are shown in Table 2.

TABLE 2

From the results of the comparative example, it can be seen that: the yield of the preparation by adopting the conventional kettle type reactor is lower than that of a micro-channel equipment system, and the selectivity of the bis [ 1-ethyl (3-oxetanyl) methyl ] ether is obviously lower than expected, so that the design requirement of product distribution cannot be met.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects as seen from the comparative examples 1 to 27 and comparative examples 1 to 5: by adopting the synthesis method provided by the application, the yield of the three oxetane compounds can be greatly improved, the reaction time can be shortened, and the co-production of the three oxetane compounds can be realized.

As can be seen from comparison of examples 1, 6, 7, 10 to 12, and 24 to 27, limiting the temperature of the transesterification reaction and the cleavage reaction to the preferred range in the present application is advantageous in increasing the total yield of the three oxetane compounds, while the ratio of the three products can also be controlled by controlling the cleavage temperature.

It is understood that the molar ratio of trimethylolpropane to the carbonate, the content of the basic catalyst used in the transesterification reaction, and the content of the basic catalyst used in the cleavage reaction are limited to the ranges preferred in the present application to be advantageous in increasing the total yield of the three oxetane compounds by comparing examples 1, 8, 9, 13 to 17, 21, and 23.

Comparing examples 1, 18, 19 and 20, it is seen that limiting the internal channel diameters of the first microreactor and the second microreactor to the preferred ranges of this application is advantageous for increasing the overall yield of the three oxetane compounds.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.